An update… I did find the thread, but it has disappeared from my “activity” list. Very curious.
The OP was Trish213,
The topic was: Laser Position is not matching what it looks like on Lightburn
So the thread did not disappear, except from the list of my recent activity. Or perhaps it disappeared from my “Notifications” list that shows up under my “avitar” when I click it.
All of this may be much ado about nothing (other than my misunderstanding about how the forum functions).